We tend to take for granted the outstanding and risky work that so many relief organizations perform around the world.

Until, that is, we’re jerked out of our comfort zones and drawn closer to the trenches — to the front lines of global conflicts, famine, plagues.

Such is the case now with the Ebola virus, a deadly disease that has aroused global fear and touched a raw nerve in America.

Fear, in this case, is a good thing. It’s an instinctive, healthy response to a scourge for which there are no effective vaccines or treatments.

It may be rooted in underdeveloped countries in West Africa, but its virulent tentacles are spreading like never before.

“Everyone should have a healthy fear of a virus, whether it’s Ebola, West Nile or the new virus, chikungunya,” said Dallas County Health and Human Services director Zachary Thompson. “We’re dealing now in an international world where viruses and diseases know no borders.”

The virus already has killed two doctors and several nurses in West Africa. It’s also threatening the lives of Dr. Kent Brantly, the Fort Worth physician who contracted the virus while treating patients in Liberia, and one of his colleagues, Nancy Writebol of North Carolina.

The nobility of their work for Samaritan’s Purse, an international relief organization, and that of other medical professionals braving the front lines of this epidemic cannot be overstated.

And we can ill afford to retreat from the vital services that such health workers and relief organizations are providing.

The U.S. Centers for Disease Control and Prevention issued a travel advisory Thursday urging Americans to avoid nonessential travel to Liberia, Guinea and Sierra Leone, the three countries at the root of the outbreak.

So obviously, organizations must figure out how to keep reaching out to that part of the world without exposing their teams of workers and volunteers to Ebola or other diseases.

Dr. Peter Linz, the international chief medical officer for Mercy Ships, said volunteers are worried about the Ebola outbreak. And they’re asking more questions.

“Obviously it’s an issue of major concern that we’ve been monitoring closely,” he said. “The actual risk [of exposure] is pretty low; the psychological risk is pretty high.”

I should note that my wife works for Mercy Ships, an international charity based in Garden City, Texas, about an hour east of Dallas. It runs the largest nongovernmental hospital ship in the world and has been in dozens of nations.

It’s now focusing on countries in West Africa. And it’s making whatever adjustments it needs — from strengthening its protocols to re-evaluating its field service — to protect its team and minimize the risk of exposure.

The next field service, for instance, has been shifted to Benin, “where there is currently no Ebola,” said Linz. And right now, he said, the ship is docked in the Canary Islands, “so we really don’t have any people on the ground in West Africa.”

Organizations must strike the right balance.

“Diseases that pop up in other parts of the world, we have to pay attention to,” Linz said. “Ebola is a real risk, a real problem. It’s affecting a part of the world with very poor health infrastructure.”

It is the possibility that the virus is only a plane or train ride away from the U.S. or other Western nations that is the most unsettling.

“That’s where the challenge is for any individual, especially Americans,” said Thompson. “I put this in the context of when we deal with the West Nile virus. We’re a 21st-century country dealing with a Third World virus.”